William c



W. CA BALLARD, Jn.-

QUENCHED SPARK GAP.

APPLICATION FILED FEB. 8,. '1918.

'Iutented Dec. 9', 1919.

FBE-

INVENTOR ing surface portion WILLIAM c. BALLARD, JR, or ITHACA, NEW YORK, AssIGNoR 'ro INTERNATIONAL SIGNAL COMPANY, A coRroRATIoN or DELAWARE.

` Specification of Letters Patent.

Patented Dee. 9, 192m.

Application led February 8, 1918. Serial No, 216,085.

To all ywhom it may concern:

Be it known that I, WILLIAM C. BALLARD, Jr., a resident of Ithaca, in the county of Tompkins and State of New York, have invented a new and useful Improvement in Quenched Spark-Gaps, of which the following is a specification. v

This invention relates to spark gaps for -radio signaling apparat-us, and particularly to gaps of the series disk or plate type, generaliy known as quenched gaps.

",he object'of the invention is to provide a gap of the character described Which not only is much cheaper to produce than similar gaps as heretofore constructed, but is also more eiiicient due to the fact that the sparking surfaces are more effectively cooled than with suoli gaps as heretofore constructed.

The invention consists in a gap consti-noted and arranged as hereinafter described.

In the accompanying drawings:

Figure l is an outside view of a portion of the improved gap showing the disks or plates in edgeivise direction; Fig. 2 is a central longitudinal section through such gap, showing one of the sparking surface members detached; and Fig. 3 is a perspective view showing the elements comprising a single unit disassembled and with the sparkomitted from one disk to illustrate the method of manufacture.

The so-called quenched gaps of the series disk type comprise a. number of disks or plates arranged in pairs, each pair constituting a single gap, and with spaces between the d'sks constituting adjacent gaps to allow for ythe circulation of air or other cooling medium. Such gaps operate most efficiently when the sparking surfaces are formed of certain metals, and generally silver is employed for this purpose. On account of the cost of the metals having the desired characteristics, it is the practice to form the plates or disks proper of a` cheaper metal, and to solder or similarly secure to the central portions thereof small disks of silver or other more expensive metal. It is necessary that the plates or disks be very accurately formed in order to secure uniform distances between the sparking surfaces and the method of manufacture above described makes the construction of such plates or disks quite costly. Furthermore. the heat produced by the sparks must be conducted through the silver disk and the baser metal outside of the same, to the air gaps between adjacent disks or plates. f

The improved gap formingthe subject of this invention is of the same general construction as the old forms, but differs in the details of its construction. As shown, the gap consists of a series of disks or plates of Which each pair forms an independent gap. In the drawings, the plates or disks 1 and 2 form a single gap, and the series of Plates When combined form a plurality of such gaps in series relation. The plates or disks l and 2 are formed of some relatively cheap metal, such as aluminum, and are either cast or stamped. Gn their outer faces they are provided with a series of bosses or protuberances 3 which contact with similar bosses on the plate of the adjacent gap to provide the necessary spaces 4 for the circulation of air or other cooling medium. On their inner faces, these plates are provided With annular gasket seats 5, which receive gaskets 6 betiveen 'the tivo plates forming the gap, and which gasket seals the -inclosed space and makes it substantially air tight.

The improved gap differs from the old forms principally in the manner of connecting the sparking surfaces to the disks. This is done in a manner to expose the outer surface of the sparking disk directly to the cooling medium, and is effected by providing each plate or disk with a central opening 7 (see Fig. 2), having around its periphery a seat 8 and an annular ilange 9, preferably on the -outer face of the plate or disk` while the sparking surface is formed of a disk 10 ofA silver or similar material, slightljv dish-shaped, with its peripheral portion ll engaging the seat 8 and having the {iange Si spun over the same. with the central o1- body portion of the disk l() projecting-slightly beyond the inner surface of the plate. To render the joint air tight, itis coated with some suitable sealing material, such as varnish, after the flange 9 is spun down.

After the disk disk or plate in disk or plate as chined, and a series of such disks or plates is then assembled, With the inner faces of each pair directed toward each other and l() is connected4 to the base the manner described, the

a Whole is accurately mai ywill be more uniform and less separated bythe gaskets 6. The peripheries of the plates are preferably provided with notches 13, in order to properly position the several plates and keep the projections or protuberances 3 in position to contact with those of the adjacent gap and maintain the maximum cooling space. f

By constructing the gap as described, the cost is very materially reduced as the soldering is entirely dispensed with and all the operations are machine operations which can be expeditiously performed, al1 parts accurately formed, and all plates will be exactly similar. Furthermore, the outer faces of the thin silver disks 10 are directly exposed to the cooling medium, so that the heat does not need to be conducted through the metal of the base disk or plate, but is directly radiated by the silver disk into the cooling mediurm The gap, therefore, is more eiiiciently cooled than the'old forms or types, and conseque-ntly is not so likely to overheat, and

operation) A Various changes can obviously be made in the shapes of' the. parts, and in the manner of or means for securing the sparking disk l() to the base plate or disk.

Vhat I claim is:

1. A spark gap of the series disk type characterized by the fact tliat'the plates or disks `are provided with openings and thin sparknig disks are secured in said openings with thelr outer faces directly exposed for subcured to said plates critical in its stantially their entire surfaces to the cooling medium.

2. A spark gap of the series disk type characterized by the'fact that plates or disks are provided with openings provided around their margins with seats and projecting por- 40 tions, and the sparking disks have their peripheries engaging said seats and are held to said seats by having the pijec'tions of the plate bent over the same, whereby the outer faces of said sparking disks are directly eX-' 45 posed tothe cooling medium.

3.' A spark gap of the series disk type characterized by the fact that the plates or disks are provided with openings, and on their outer surfaces with spacing members, and sparking 'disks closing said openings and/ sewith their outer faces directly exposed to the cooling medium.

4. A spark gap of 'the series disk type characterized by the fact that the plates or disks are provided with openings and on their inner faces with gasket seats, and the sparking surfaces are secured in said openings with an air tight joint and with their outer faces ydirectly exposed to the cooling medium and sealing gaskets interposed between 'the gasket seats of adjacent disks. l

In testimony whereof I have hereunto set my hand.

WM. C. BALLARD, JR. Witnesses:

MARTIN C.' HUGHES, JOHN Gr. PERTSCH, J r. 

